rounding rope

[matfio]

hello to all
I open this thread in this section because visiting this forum these days I discovered how many people underestimate the string rounding.
I know that other users are also very interested in both the subject and the skills that in my opinion has shown the borntired user.
was discussing the importance and difference between a string rounding and a "normal".
attached an example of a rope beam made in tangency(g1) and one in flow(g3) with nx.

for you how important it can be in product design the cord rounding?
What do you think?

 

[ceschi1959]

hi matfio, I also read the thread to which you mentioned and I was impressed by the clear competence of the borntired user with which I would like to resume the speech on this and also other topics of the type blend corner. this in order to exchange design skills in the spirit of the forum.

bye:

 

[cacciatorino]

In order to facilitate understanding even to those who do not deal with style, like me for example, can you explain to us the importance and application of this function, and why is it used in industry?

 

[flaviobrio88]

I personally know this kind of fillet, but I've always asked myself the same hunting question, why and what's it for?

 

[matfio]

for me it is important because the quality of the surfaces is also seen in the printed (thermoplastic), the mill works better (stampo)

 

[cacciatorino]

for me it is important because the quality of the surfaces is also seen in the printed (thermoplastic), the mill works better (stampo)

Could you be more technical and thorough? so I still don't understand the usefulness of this function.

 

[Fulvio Romano]

The rope blend serves to make style rays on surfaces with a variable angle. It's what everyone knows about style. Well, maybe not.
the classic problem of the rays is that they produce very clean light strokes. If they are technical rays, this is not a problem, because the eye always reads them and anyway as living edges. but if they are rays of style it is important that the "colpo di luce" follow the theoretical profile of the living edge, which is what the eye tends to follow. a constant radius (so of variable width) instead produces a light blow that moves away from the living edge when the angle of incidence is lowered, and vice versa approaches when the angle rises.
the rope blend solves this problem.

pippe by architects, ok, but of some importance in the world of style.

Oh, I'm saying, it's not like we're "a bunch of architects," it triggers a flame, is it? with the air pulling...

 

[ceschi1959]

Bye to all,

rope blend, usually used for rays greater than 5 (usually below this threshold there are no great differences), connects in g2 or g3 the surfaces giving a better aesthetic effect.
a workaround, but not from identical results, is to pass a tube using as axis the intersection of the surfaces, cut the same with the tube and then let us pass a surface of blend.
attached two rays on two flat surfaces 'zebrates' where you can see how light is reflected in a different way. on top the 'normal' blend the cord at the bottom.

Hi.

 

[cacciatorino]

So, since we're in a technical forum, I expect a little more interesting considerations of the fact that the piece is so nicer, or that the audi use this method.

so let's do one thing: who wants to intervene documents well before posting messages, so that the messages themselves are high "specific weight": For example, explain to me what mathematically means a g2 or g1 or g0 continuity, and why a g2 surface produces a better result than a g1 surface, or because the constant rope radius reflects uniformly and the constant radius instead does not.

Let's show that we're technical and not coffee makers, courage! :smile:

 

[matfio]

if you go even more in the technician you have to start to keep an eye on the degrees of a superfice and direction of the iso u/v but here it pushes of style that many times does not serve because of the product and the finishes.
according to me remain important the notices that are all kinds of fittings also those on edge see thread http://www.cad3d.it/forum1/showthread.php?t=34395

 

[Fulvio Romano]

So, since we're in a technical forum, I expect a little more interesting considerations of the fact that the piece is so nicer, or that the audi use this method.

So let's do one thing: who wants to intervene is documented well before posting messages, so that the messages are high "specific weight", for example explain to me what it means from the mathematical point of view a continuity' g2 or g0, and why a g2 surface produces a better result of a g1 surface, or because the constant string radius reflects uniformly and the constant ray instead does not.

Let's show that we're technical and not coffee makers, courage! :smile:

Wasn't I technical enough in my post?
the question is purely aesthetic, there is no other motivation.

attention to the speech g1 and g2... some inaccuracies have been said about which I overwhelmed.
apart from the fact that I have not yet understood the difference between g and c, who knows if a zimmy randomly will explain to me, but the "roy" is by definition a radius...continuous. will therefore be in continuity c1 That's enough. unless it is the surface designed ad hoc.

Besides... A string blend is not a radius, it's a blend. Perhaps it is useless that I explain why.

 

[cacciatorino]

Besides... A string blend is not a radius, it's a blend. Perhaps it is useless that I explain why.

No, no, no, no, no, no, no, no, no, no, no, no, no, no, no.

but the considerations more than I expect from you from those who opened the discussion explicitly speaking of g1 and g3, I expect a very exhaustive discussion on the subject: Because it's considered so important, knowledge is very thorough.

 

[flaviobrio88]

The rope blend serves to make style rays on surfaces with a variable angle. It's what everyone knows about style. Well, maybe not.
...

received:


actually the result is very different

 

[Fulvio Romano]

No, no, no, no, no, no, no, no, no, no, no, no, no, no, no.

the "roar" or "fillet" is the surface whose orthogonal section is the place of the points equidistant from a point, called center, and in tangence with adjacent surfaces.

is not defined the degree, because it is a conical* and not a polynomial. in principle the surface at the end of the radius will have a curvature (and therefore a radius) other than that of the radius itself.

then, input data: radius and adjacent surfaces; output data, center location and arc length, uniquely determined.

What happens mathematically if I try to make a "roy" and try to impose also the bond that the rope is of constant length? I've got a nice, super-vine system without a solution.

then I lose a bond, that is that the surface has constant radius. the result will no longer be a conical*, but will satisfy me on the bond of constant rope. What curve do I choose? Well, obviously a nurbs, because it is a rather powerful tool, even if not the only one. Unfortunately, however, the nurbs is characterized by a system of equations strongly subvinculated, I must therefore add some constraint. up to low degrees I can ask continuity g-superiors, besides, I should ask maximum (but it is also excessive) a g3 and equally distribute the remaining polynomial weights.
the surface that comes out is called "blend", because it "breaks" the two surfaces that try to reconnect.

This is a ludic-mathematic treatment. However, making a radius of a few centimetres with degrees above 3-5 means unnecessarily slaughtering the surfaces.

then... every one has their own tastes. "The surface is mine and I manage it," right?

(*)
Yes, okay, it's not a conical, but the sweep of a conical along a curve... eccheppalle! :tongue:

 

[matfio]

continuity describes the behaviour of surfaces and curves to their segment contours. the two types of continuity with which it is to do are the geometric continuity indicated by gn where "n" represents an entire and mathematical continuity indicated by cn.

continuity
gn indicates the real degree of continuity between two geometric objects.
for example:
g0 means that the two objects are connected, or that are in continuity position.
g1 means that they are connected but with a differentiation or that are in continuity of tangency.
g2 means that they are connected but with two differentiations or that are in continuity of curvature.
g3 means that they are connected but with three differentiations, etc.
gn continuity are independent representations (parameters)


continuity
cn indicates the degree of continuity between two segments of a b-curva or a b-superficie in a non-uniform representation rational b-spline (nurb). generically c0 means that the two segments connected to g0.
c1 means that they are connected to g1 etc.
but c0 does not mean that the two segments are only connected to g0 could actually be connected to g1 or g2 and so on.
The key point is that gn represents physical continuity while cn is a mathematical representation that may not be faithful.

 

[cacciatorino]

continuity describes the behaviour of surfaces and curves to their segment contours. the two types of continuity with which it is to do are the geometric continuity indicated by gn where "n" represents an entire and mathematical continuity indicated by cn.

and how does this link to the need for a constant-quota connection? I can have the continuity of the fitting curves independently of the length of this fitting, in fact from the beginning I did not understand the relationship between the speech of the continuity' in curvature and the consistency of the length of the connection.

Anyway, math continuity, I think we can give assign to knowing what it is, what I haven't understood yet is because it's important to have uniformly continuous surfaces.

 

[Fulvio Romano]

continuity describes the behaviour of surfaces and curves to their segment contours. the two types of continuity with which it is to do are the geometric continuity indicated by gn where "n" represents an entire and mathematical continuity indicated by cn.

continuity
gn indicates the real degree of continuity between two geometric objects.
for example:
g0 means that the two objects are connected, or that are in continuity position.
g1 means that they are connected but with a differentiation or that are in continuity of tangency.
g2 means that they are connected but with two differentiations or that are in continuity of curvature.
g3 means that they are connected but with three differentiations, etc.
gn continuity are independent representations (parameters)


continuity
cn indicates the degree of continuity between two segments of a b-curva or a b-superficie in a non-uniform representation rational b-spline (nurb). generically c0 means that the two segments connected to g0.
c1 means that they are connected to g1 etc.
but c0 does not mean that the two segments are only connected to g0 could actually be connected to g1 or g2 and so on.
The key point is that gn represents physical continuity while cn is a mathematical representation that may not be faithful.

Can I give you a little note?
if you make a copy and paste from here: http://www.viewmold.com/ug_html_files/modeling/apx_continuity.html and then translate with the automatic translator, you don't understand anything.. .

that the text is disgrammated, but if you translate "smoothly connected up to one differentation" with "linked but with a differentiation", it is very different from correctly translating "linked up to the derivative first".

 

[Fulvio Romano]

The key point is that gn represents physical continuity while cn is a mathematical representation that may not be faithful.

ahhh.... now I understand! and it was enough to copy the rest:

g1 implies that the tangent vectors are equal in direction, but not magnitude. g2 implies the curvature is the same, but the second derivatives are not

or continuity of type "cn" means that the n-th derivative is equal in the two surfaces, that is, that the vector (eg tangency) coincides as direction, towards (vabbé, obviously opposite) and magnitude.
the continuity of type "gn" is a little less stringent, the carrier coincides as direction and direction (opposed), but not in size. that is the norm of the gradient (the verse) coincides, but its determining no.

Clearly. Finally! :wink:

 

[cacciatorino]

Dearest users, I'm closing down the discussion because I have to be absent, I'm going back to 7:00.

Meanwhile, those who opened the discussion can search for documentation and literature from which to demonstrate the importance of the function described.

 

[matfio]

ahhh.... now I understand! and it was enough to copy the rest:


or continuity of type "cn" means that the n-th derivative is equal in the two surfaces, that is, that the vector (eg tangency) coincides as direction, towards (vabbé, obviously opposite) and magnitude.
the continuity of type "gn" is a little less stringent, the carrier coincides as direction and direction (opposed), but not in size. that is the norm of the gradient (the verse) coincides, but its determining no.

Clearly. Finally! :wink:

I... you caught me, cmq I didn't translate anything I copied almost equal from the documentation in Italian of nx.... .... discovered